In the construction of buildings, tapered workpieces, such as shims, are commonly used. Shims are used to fill gaps; to level items such as doors, windows, cabinets; or to adjust such items to fit properly. In the past, shims have traditionally been made of wood, sometimes simply from scrap pieces found on the job site and fashioned by the craftsman to suit the task. In order to provide a ready supply and to overcome the inconvenience of manually creating them, manufacturers have produced wooden shims and sold them in bundles. Experience shows, however, that such manufactured shims are often not useable because of knots and cracks inherent in the secondary wood used to create them. In fact, as much as one-half of a bundle of manufactured wooden shims is generally unusable because of such defects.
Moreover, the wood used to manufacture shims is not subjected to the same quality control or care as are the better grades of wood. Although the moisture content of Grade A lumber is maintained by soaking it in water up until delivery, secondary wood usually does not receive such care and thus becomes exceedingly brittle and dry by the time it is ready for use. Shims made of such secondary wood will often split or disintegrate upon the slight impression of force needed to hammer them into a shim space.
After shims are set in a door frame or window jamb, their excess lengths must be broken off so as to allow for a uniform substrate against which to install drywall. The wooden shims in common use must be scored with a razor knife and then broken off with a hammer tap. This procedure often results in disintegration or breakage of the shims because of the poor and inconsistent quality of the wood used.
Not only does the described practice waste wood, it would be better if shims and the like were made from other materials. There are ever-increasing concerns for the preservation of forests, and thus the availability of manufactured shims and other wood products is uncertain. Still, it has not previously been recognized that conventionally shaped shims need not be made of wood but could be made of recyclable materials while improving the characteristics of the shims.
Furthermore, the handling and storing of wooden shims prior to use has not been convenient or efficient. Even manufactured bundles are cumbersome to handle and do not lend themselves to compact storage and transport, particularly after unbundling. Again, because of the quality of the wood used, wooden shims are more prone to damage while being transported and stored.
The U.S. Pat. No. 5,163,255 to Gamba provides a wooden block which is saw-cut into a plurality of wooden shims. The Gamba shims are still wood and have the disadvantages of wooden shims, as discussed above. In addition, each shim has a burr or remnant on its working face because of the wood breakage which prevents intimate mating contact with the surface or item to be leveled or adjusted. The U.S. Pat. No. 5,0554,250 to Foss provides a plastic shim, thereby avoiding the disadvantages of wood, but it is not the shape and design of the common shim which is the accepted standard for conventional construction. The U.S. patent to Trussell discloses a metal shim for use in alignment of automobile front ends, but such a shim would not be an acceptable shim for a carpenter to carry, store or use in the building trades.